Liquid crystal display device

ABSTRACT

According to one embodiment, a liquid crystal display device includes a main pixel electrode which extends in a second direction, a sub-pixel electrode which extends in a first direction and crosses the main pixel electrode, a color filter which includes a first aperture portion defined by a first edge surrounding a position opposed to cross points between the main pixel electrode and the sub-pixel electrode, main common electrodes which extend in the second direction on both sides of the main pixel electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2011-172849, filed Aug. 8, 2011,the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a liquid crystaldisplay device.

BACKGROUND

In recent years, flat-panel display devices have been vigorouslydeveloped. By virtue of such advantageous features as light weight,small thickness and low power consumption, special attention has beenpaid to liquid crystal display devices among others. In particular, inactive matrix liquid crystal devices in which switching elements areincorporated in respective pixels, attention is paid to theconfiguration which makes use of a lateral electric field (including afringe electric field), such as an IPS (In-Plane Switching) mode or anFFS (Fringe Field Switching) mode. Such a liquid crystal display deviceof the lateral electric field mode includes pixel electrodes and acounter-electrode, which are formed on an array substrate, and liquidcrystal molecules are switched by a lateral electric field which issubstantially parallel to a major surface of the array substrate.

On the other hand, there has been proposed a technique wherein a lateralelectric field or an oblique electric field is produced between a pixelelectrode formed on an array substrate and a counter-electrode formed ona counter-substrate, thereby switching liquid crystal molecules.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view which schematically illustrates a structure and anequivalent circuit of a liquid crystal display device according to anembodiment.

FIG. 2 is a plan view which schematically shows a structure example of apixel at a time when an array substrate shown in FIG. 1 is viewed from acounter-substrate side.

FIG. 3 is a plan view which schematically shows a structure example of apixel in the counter-substrate shown in FIG. 1.

FIG. 4 is a schematic cross-sectional view, taken along line A-A in FIG.2, showing a cross-sectional structure of a liquid crystal display panelshown in FIG. 2.

FIG. 5 is a schematic cross-sectional view, taken along line B-B in FIG.2, showing a cross-sectional structure of the liquid crystal displaypanel shown in FIG. 2.

FIG. 6 is a view showing light transmission states at times when blackdisplay, low-gray-level display, intermediate-gray-level display andhigh-gray-level display (white display) were effected in one pixel.

FIG. 7 is a plan view which schematically shows a shape of a colorfilter in the embodiment.

FIG. 8 is a graph showing an example of spectral transmittances ofrespective color filters and a spectral transmittance at an apertureportion.

FIG. 9 is a chromaticity diagram showing an example of a colorreproduction range at a time of low-gray-level display and a colorreproduction range at a time of high-gray-level display in a case wherethe color filters of the embodiment are applied.

FIG. 10 is a plan view which schematically shows another shape of thecolor filter in the embodiment.

FIG. 11 is a plan view which schematically shows another shape of thecolor filter in the embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a liquid crystal display deviceincludes: a first substrate including a first gate line and a secondgate line which extend in a first direction, a storage capacitance linewhich extends in the first direction between the first gate line and thesecond gate line, a first source line and a second source line whichextend in a second direction crossing the first direction, a switchingelement which is electrically connected to the first gate line and thefirst source line, a main pixel electrode which extends in the seconddirection between the first source line and the second source line, asub-pixel electrode which extends in the first direction, iselectrically connected to the switching element, crosses the main pixelelectrode and is continuous with the main pixel electrode, and a firstalignment film which covers the main pixel electrode and the sub-pixelelectrode; a second substrate including a color filter which includes afirst aperture portion defined by a first edge surrounding a positionopposed to cross points between the main pixel electrode and thesub-pixel electrode, an overcoat layer which covers the color filter andextends over the first aperture portion, main common electrodes whichextend in the second direction on both sides of the main pixel electrodeon that side of the overcoat layer, which is opposed to the firstsubstrate, and a second alignment film which covers the main commonelectrodes; and a liquid crystal layer including liquid crystalmolecules held between the first substrate and the second substrate.

According to one embodiment, a liquid crystal display device includes: afirst substrate including a first gate line and a second gate line whichextend in a first direction, a storage capacitance line which extends inthe first direction at a substantially middle point between the firstgate line and the second gate line, a first source line and a secondsource line which extend in a second direction crossing the firstdirection, a switching element which is electrically connected to thefirst gate line and the first source line, a cross-shaped pixelelectrode including a main pixel electrode, which extends in the seconddirection between the first source line and the second source line, anda sub-pixel electrode, which is located above the storage capacitanceline, is electrically connected to the switching element, crosses themain pixel electrode and extends in the first direction, and a firstalignment film which covers the pixel electrode; a second substrateincluding a color filter which includes a first aperture portion definedby a first edge surrounding a position opposed to first to fourth crosspoints between the main pixel electrode and the sub-pixel electrode at acentral part of the pixel, an overcoat layer which covers the colorfilter and extends over the first aperture portion, main commonelectrodes which extend in the second direction on both sides of themain pixel electrode on that side of the overcoat layer, which isopposed to the first substrate, and a second alignment film which coversthe main common electrodes; and a liquid crystal layer including liquidcrystal molecules held between the first substrate and the secondsubstrate.

Embodiments will now be described in detail with reference to theaccompanying drawings. In the drawings, structural elements having thesame or similar functions are denoted by like reference numerals, and anoverlapping description is omitted.

FIG. 1 is a view which schematically shows a structure and an equivalentcircuit of a liquid crystal display device according to an embodiment.

Specifically, the liquid crystal display device includes anactive-matrix-type liquid crystal display panel LPN. The liquid crystaldisplay panel LPN includes an array substrate AR which is a firstsubstrate, a counter-substrate CT which is a second substrate that isdisposed to be opposed to the array substrate AR, and a liquid crystallayer LQ which is disposed between the array substrate AR and thecounter-substrate CT. The liquid crystal display panel LPN includes anactive area ACT which displays an image. The active area ACT is composedof a plurality of pixels PX which are arrayed in a matrix of m×n (m andn are positive integers).

The liquid crystal display panel LPN includes, in the active area ACT,an n-number of gate lines G (G1 to Gn), an n-number of storagecapacitance lines C (C1 to Cn), and an m-number of source lines S (S1 toSm). The gate lines G and storage capacitance lines C correspond tosignal lines extending substantially linearly, for example, in a firstdirection X. The gate lines G and storage capacitance lines C neighborat intervals along a second direction Y crossing the first direction X,and are alternately arranged in parallel. In this example, the firstdirection X and the second direction Y are perpendicular to each other.The source lines S cross the gate lines G and storage capacitance linesC. The source lines S correspond to signal lines extending substantiallylinearly along the second direction Y. It is not always necessary thateach of the gate lines G, storage capacitance lines C and source lines Sextend linearly, and a part thereof may be bent.

Each of the gate lines G is led out to the outside of the active areaACT and is connected to a gate driver GD. Each of the source lines S isled out to the outside of the active area ACT and is connected to asource driver SD. At least parts of the gate driver GD and source driverSD are formed on, for example, the array substrate AR, and are connectedto a driving IC chip 2 which incorporates a controller.

Each of the pixels PX includes a switching element SW, a pixel electrodePE and a common electrode CE. A storage capacitance CS is formed, forexample, between the storage capacitance line C and the pixel electrodePE. The storage capacitance line C is electrically connected to avoltage application module VCS to which a storage capacitance voltage isapplied.

In the present embodiment, the liquid crystal display panel LPN isconfigured such that the pixel electrodes PE are formed on the arraysubstrate AR, and at least a part of the common electrode CE is formedon the counter-substrate CT, and liquid crystal molecules of the liquidcrystal layer LQ are switched by mainly using an electric field which isproduced between the pixel electrodes PE and the common electrode CE.The electric field, which is produced between the pixel electrodes PEand the common electrode CE, is an oblique electric field which isslightly inclined to an X-Y plane which is defined by the firstdirection X and second direction Y, or to a substrate major surface ofthe array substrate AR or a substrate major surface of thecounter-substrate CT (or a lateral electric field which is substantiallyparallel to the substrate major surface).

The switching element SW is composed of, for example, an n-channelthin-film transistor (TFT). The switching element SW is electricallyconnected to the gate line G and source line S. The switching element SWmay be of a top gate type or a bottom gate type. In addition, asemiconductor layer of the switching element SW is formed of, forexample, polysilicon, but it may be formed of amorphous silicon.

The pixel electrodes PE are disposed in the respective pixels PX, andare electrically connected to the switching elements SW. The commonelectrode CE has, for example, a common potential, and is disposedcommon to the pixel electrodes PE of plural pixels PX via the liquidcrystal layer LQ. The pixel electrodes PE and common electrode CE areformed of a light-transmissive, electrically conductive material such asindium tin oxide (ITO) or indium zinc oxide (IZO). However, the pixelelectrodes PE and common electrode CE may be formed of other metallicmaterial such as aluminum.

The array substrate AR includes a power supply module VS for applying avoltage to the common electrode CE. The power supply module VS isformed, for example, on the outside of the active area ACT. The commonelectrode CE is led out to the outside of the active area ACT, and iselectrically connected to the power supply module VS via an electricallyconductive member (not shown).

FIG. 2 is a plan view which schematically shows a structure example ofone pixel PX at a time when the array substrate AR shown in FIG. 1 isviewed from the counter-substrate side. FIG. 2 is a plan view in an X-Yplane.

The array substrate AR includes a gate line G1, a gate line G2, astorage capacitance line C1, a source line S1, a source line S2, aswitching element SW, a pixel electrode PE, and a first alignment filmAL1. In the example illustrated, the array substrate AR further includesa part of a common electrode CE.

The gate line G1, gate line G2 and storage capacitance line C1 extend inthe first direction X. The source line S1 and source line S2 extend inthe second direction Y. The storage capacitance line C1 is located at asubstantially middle point between the gate line G1 and the gate lineG2. Specifically, the distance between the gate line G1 and the storagecapacitance line C1 in the second direction Y is substantially equal tothe distance between the gate line G2 and the storage capacitance lineC1 in the second direction Y.

In the example illustrated, the pixel PX corresponds to a grid regionwhich is formed by the gate line G1, gate line G2, source line S1 andsource line S2, as indicated by a broken line in FIG. 2. The pixel PXhas a rectangular shape having a greater length in the second directionY than in the first direction X. The length of the pixel PX in the firstdirection X corresponds to a pitch between the source line S1 and sourceline S2 in the first direction X. The length of the pixel PX in thesecond direction Y corresponds to a pitch between the gate line G1 andgate line G2 in the second direction Y. The pixel electrode PE isdisposed between the source line S1 and source line S2 which neighboreach other. In addition, the pixel electrode PE extends immediatelyabove the storage capacitance line C1 and is located between the gateline G1 and gate line G2.

In the example illustrated, in the pixel PX, the source line S1 isdisposed at a left side end portion, the source line S2 is disposed at aright side end portion, the gate line G1 is disposed at an upper sideend portion, and the gate line G2 is disposed at a lower side endportion. Strictly speaking, the source line S1 is disposed to extendover a boundary between the pixel PX and a pixel neighboring on the leftside, the source line S2 is disposed to extend over a boundary betweenthe pixel PX and a pixel neighboring on the right side, the gate line G1is disposed to extend over a boundary between the pixel PX and a pixelneighboring on the upper side, and the gate line G2 is disposed toextend over a boundary between the pixel PX and a pixel neighboring onthe lower side. The storage capacitance line C1 is disposed at asubstantially central part of the pixel PX. A region where the storagecapacitance line C1 and the source line S1 cross is a first intersectionpart CR1, and a region where the storage capacitance line C1 and thesource line S2 cross is a second intersection part CR2. The firstintersection part CR1 and second intersection part CR2 are regionsindicated by hatching lines in FIG. 2.

A switching element SW in the illustrated example is electricallyconnected to the gate line G1 and source line S1. The switching elementSW is provided at an intersection between the gate line G1 and sourceline S1. A gate electrode WG of the switching element SW is electricallyconnected to the gate line G1, and a source electrode WS of theswitching element SW is electrically connected to the source line S1. Adrain electrode WD of the switching element SW is formed to extend alongthe source line S1 and storage capacitance line C1, and is electricallyconnected to the pixel electrode PE via a contact hole CH formed in anarea overlapping the storage capacitance line C1. The switching elementSW is provided in an area overlapping the source line S1 and storagecapacitance line C1, and does not substantially protrude from the areaoverlapping the source line S1 and storage capacitance line C1, thussuppressing a decrease in area of an aperture portion which contributesto display.

The pixel electrode PE includes a main pixel electrode PA and asub-pixel electrode PB. The main pixel electrode PA and sub-pixelelectrode PB are formed to be integral or continuous, and areelectrically connected to each other. In the meantime, in the exampleillustrated, only the pixel electrode PE which is disposed in one pixelPX is shown, but pixel electrodes of the same shape are disposed inother pixels, the depiction of which is omitted.

The main pixel electrode PA linearly extends in the second direction Y,between the source line S1 and source line S2, from the sub-pixelelectrode PB to the vicinity of the upper side end portion of the pixelPX and to the vicinity of the lower side end portion of the pixel PX.The main pixel electrode PA is formed in a strip shape having asubstantially equal width along the first direction X.

The sub-pixel electrode PB linearly extends in the first direction Xfrom the main pixel electrode PA toward the source line S1 and sourceline S2. The sub-pixel electrode PB is disposed at a region which isopposed to the storage capacitance line C1, and is electricallyconnected to the drain electrode WD of the switching element SW via thecontact hole CH. The sub-pixel electrode PB is formed in a strip shapealong the X direction with a width which is greater than the width ofthe main pixel electrode PA. The sub-pixel electrode PB is locatedbetween the first intersection part CR1 and second intersection partCR2. The sub-pixel electrode PE shown in the Figure crosses anintermediate part of the main pixel electrode PA, and the pixelelectrode PE has a cross shape.

The pixel electrode PE is disposed at a substantially middle pointbetween the source line S1 and source line S2, that is, at the center ofthe pixel PX. The distance in the first direction X between the sourceline S1 and main pixel electrode PA is substantially equal to thedistance in the first direction X between the source line S2 and themain pixel electrode PA.

The common electrode CE includes first main common electrodes CA1 andfirst sub-common electrodes CB1 on the array substrate AR. The firstmain common electrodes CA1 and first sub-common electrodes CB1 areformed to be integral or continuous with each other, and areelectrically to each other. Specifically, the first main commonelectrodes CA1 and first sub-common electrodes CB1 are disposed in amanner to surround the pixel electrode PE, and are spaced a part fromthe pixel electrode PE.

The first main common electrodes CA1 extend, in the X-Y plane, linearlyin the second direction Y that is substantially parallel to the mainpixel electrode PA, on both sides of the main pixel electrode PA.Alternatively, the first main common electrodes CA1 are opposed to thesource lines S and extend substantially in parallel to the main pixelelectrode PA. The first main common electrode CA1 is formed in a stripshape having a substantially equal width in the first direction X. Inaddition, the first main common electrodes CA1 are broken at positionson both sides of the sub-pixel electrode PB. Specifically, the firstmain common electrodes CA1 are broken at the first intersection part CR1and second intersection part CR2.

In the example illustrated, two first main common electrodes CA1 arearranged in parallel with a distance in the first direction X, and arelocated at left and right end portions of the pixel PX, respectively. Inthe description below, in order to distinguish these first main commonelectrodes CA1, the first main common electrode located on the left sideof the pixel PX is referred to as “CAL1”, and the first main commonelectrode located on the right side is referred to as “CAR1”. Strictlyspeaking, the first main common electrode CAL1 is disposed to extendover a boundary between the pixel PX and a pixel neighboring on the leftside, and the first main common electrode CAR1 is disposed to extendover a boundary between the pixel PX and a pixel neighboring on theright side. The first main common electrode CAL1 is broken at theintersection part CR1 and is opposed to the source line S1 at the otherpositions. The first main common electrode CAR1 is broken at theintersection part CR2 and is opposed to the source line S2 at the otherpositions.

The first sub-common electrodes CB1 extend, in the X-Y plane, linearlyin the first direction X that is substantially parallel to the sub-pixelelectrode PB, on both sides of the sub-pixel electrode PB.Alternatively, the first sub-common electrodes CB1 are opposed to thegate lines G and extend substantially in parallel to the sub-pixelelectrode PB. The first sub-common electrode CB1 is formed in a stripshape. The width in the second direction Y of the first sub-commonelectrode CB1 may not necessarily be uniform. In addition, the firstsub-common electrodes CB1 are formed integral or continuous with thefirst main common electrodes CA1, and are electrically connected to thefirst main common electrodes CA1. Specifically, the first sub-commonelectrodes CB1 have the same potential as the first main commonelectrodes CA1.

In the example illustrated, two first sub-common electrodes CB1 arearranged in parallel with a distance in the second direction Y, and aredisposed at upper and lower end portions of the pixel PX, respectively.In the description below, in order to distinguish these first sub-commonelectrodes CB1, the first sub-common electrode located on the upper sideof the pixel PX is referred to as “CBU1”, and the first sub-commonelectrode located on the lower side of the pixel PX is referred to as“CBB1”. Strictly speaking, the first sub-common electrode CBU1 isdisposed to extend over a boundary between the pixel PX and a pixelneighboring on the upper side, and the first sub-common electrode CBB1is disposed to extend over a boundary between the pixel PX and a pixelneighboring on the lower side. The first sub-common electrode CBU1 isopposed to the gate line G1, without being broken at an intermediatepart thereof. The first sub-common electrode CBB1 is opposed to the gateline G2, without being broken at an intermediate part thereof.

Paying attention to the positional relationship between the pixelelectrode PE and the common electrode CE, the following relationship isestablished.

In the X-Y plane, the main pixel electrode PA and the first main commonelectrodes CA1 are alternately arranged along the first direction X. Themain pixel electrode PA and the first main common electrodes CA1 arearranged substantially parallel to each other. In this case, in the X-Yplane, neither of the first main common electrodes CA1 overlaps thepixel electrode PE. Specifically, one main pixel electrode PA is locatedbetween the first main common electrode CAL1 and first main commonelectrode CAR1 which neighbor each other with a distance in the firstdirection X. In other words, the first main common electrode CAL1 andfirst main common electrode CAR1 are disposed on both sides of the mainpixel electrode PA. Thus, the first main common electrode CAL1, mainpixel electrode PA and first main common electrode CAR1 are arranged inthe named order along the first direction X. The distance in the firstdirection X between the main pixel electrode PA and each of the firstmain common electrodes CA1 is substantially uniform. Specifically, thedistance in the first direction X between the first main commonelectrode CAL1 and the main pixel electrode PA is substantially equal tothe distance in the first direction X between the first main commonelectrode CAR1 and the main pixel electrode PA.

In the X-Y plane, the sub-pixel electrode PB and the first sub-commonelectrodes CB1 are alternately arranged along the second direction Y.The sub-pixel electrode PB and the first sub-common electrodes CB1 arearranged substantially parallel to each other. In this case, in the X-Yplane, neither of the first sub-common electrodes CB1 overlaps the pixelelectrode PE. Specifically, one sub-pixel electrode PB is locatedbetween the first sub-common electrode CBU1 and first sub-commonelectrode CBB1 which neighbor each other with a distance in the seconddirection Y. In other words, the first sub-common electrode CBU1 andfirst sub-common electrode CBB1 are disposed on both sides of thesub-pixel electrode PB. Thus, the first sub-common electrode CBB1,sub-pixel electrode PB and first sub-common electrode CBU1 are arrangedin the named order along the second direction Y. The pixel electrode PE,first main common electrodes CA1 and first sub-common electrodes CB1,which are shown in FIG. 2, are covered with the first alignment filmAL1.

FIG. 3 is a plan view which schematically shows a structure example ofone pixel PX in the counter-substrate CT shown in FIG. 1. FIG. 3 is aplan view in the X-Y plane. FIG. 3 shows only parts which are necessaryfor the description, and indicates, by broken lines, the pixel electrodePE, first main common electrodes CA1 and first sub-common electrodes CB1which are provided on the array substrate.

The common electrode CE includes second main common electrodes CA2 andsecond sub-common electrodes CB2 on the counter-substrate CT. The secondmain common electrodes CA2 and second sub-common electrodes CB2 areelectrically connected to the first main common electrodes CA1 and firstsub-common electrodes CB1 provided on the array substrate, for example,on the outside of the active area. Specifically, the second main commonelectrodes CA2 and second sub-common electrodes CB2 have the samepotential as the first main common electrodes CA1 and first sub-commonelectrodes CB1.

The second main common electrodes CA2 extend, in the X-Y plane, linearlyin the second direction Y that is substantially parallel to the mainpixel electrode PA, on both sides of the main pixel electrode PA.Alternatively, the second main common electrodes CA2 are opposed to thefirst main common electrodes CA1 and extend substantially in parallel tothe main pixel electrode PA. The second main common electrode CA2 isformed in a strip shape having a substantially equal width in the firstdirection X.

In the example illustrated, two second main common electrodes CA2 arearranged in parallel with a distance in the first direction X, and arelocated at left and right end portions of the pixel PX, respectively. Inthe description below, in order to distinguish these second main commonelectrodes CA2, the second main common electrode located at the leftside end portion of the pixel PX is referred to as “CAL2”, and thesecond main common electrode located at the right side end portion ofthe pixel PX is referred to as “CAR2”. Strictly speaking, the secondmain common electrode CAL2 is disposed to extend over a boundary betweenthe pixel PX and a pixel neighboring on the left side, and the secondmain common electrode CAR2 is disposed to extend over a boundary betweenthe pixel PX and a pixel neighboring on the right side. The second maincommon electrode CAL2 is opposed to the first main common electrodeCAL1, without being broken at an intermediate portion thereof. Thesecond main common electrode CAR2 is opposed to the first main commonelectrode CAR1, without being broken at an intermediate portion thereof.

The second sub-common electrodes CB2 extend, in the X-Y plane, linearlyin the first direction X that is substantially parallel to the sub-pixelelectrode PB, on both sides of the sub-pixel electrode PB.Alternatively, the second sub-common electrodes CB2 are opposed to thefirst sub-common electrodes CB1 and extend substantially in parallel tothe sub-pixel electrode PB. The second sub-common electrode CB2 isformed in a strip shape having a substantially equal width in the seconddirection Y. In addition, the second sub-common electrodes CB2 areformed integral or continuous with the second main common electrodesCA2, and are electrically connected to the second main common electrodesCA2. Specifically, in the counter-substrate CT, the common electrode CEis formed in a grid shape.

In the example illustrated, two second sub-common electrodes CB2 arearranged in parallel with a distance in the second direction Y, and aredisposed at upper and lower end portions of the pixel PX, respectively.In the description below, in order to distinguish these secondsub-common electrodes CB2, the second sub-common electrode located atthe upper end portion of the pixel PX is referred to as “CBU2”, and thesecond sub-common electrode located at the lower end portion of thepixel PX is referred to as “CBB2”. Strictly speaking, the secondsub-common electrode CBU2 is disposed to extend over a boundary betweenthe pixel PX and a pixel neighboring on the upper side, and the secondsub-common electrode CBB2 is disposed to extend over a boundary betweenthe pixel PX and a pixel neighboring on the lower side. The secondsub-common electrode CBU2 is opposed to the first sub-common electrodeCBU1, without being broken at an intermediate part thereof. The secondsub-common electrode CBB2 is opposed to the first sub-common electrodeCBB1, without being broken at an intermediate part thereof. Each of thesecond main common electrodes CA2 and second sub-common electrodes CB2,which are shown in FIG. 3, is covered with a second alignment film AL2.

FIG. 4 is a schematic cross-sectional view, taken along line A-A in FIG.2, showing a cross-sectional structure of the liquid crystal displaypanel LPN shown in FIG. 2. FIG. 5 is a schematic cross-sectional view,taken along line B-B in FIG. 2, showing a cross-sectional structure ofthe liquid crystal display panel LPN shown in FIG. 2. FIG. 4 and FIG. 5show only parts which are necessary for the description.

A backlight 4 is disposed on the back side of the array substrate ARwhich constitutes the liquid crystal display panel LPN. Various modesare applicable to the backlight 4. As the backlight 4, use may be madeof either a backlight which utilizes a light-emitting diode (LED) as alight source, or a backlight which utilizes a cold cathode fluorescentlamp (CCFL) as a light source. A description of the detailed structureof the backlight 4 is omitted.

The array substrate AR is formed by using a first insulative substrate10 having light transmissivity. The array substrate AR includes, on theinside of the first insulative substrate 10, a gate line G1, a gate lineG2, a storage capacitance line C1, a source line S1, a source line S2, apixel electrode PE, a common electrode CE, a first insulation film 11, asecond insulation film 12, a third insulation film 13, and a firstalignment film AL1.

The gate line G1, gate line G2 and storage capacitance line C1 areformed on the first insulation film 11, and are covered with the secondinsulation film 12. The source line S1 and source line S2 are formed onthe second insulation film 12 and are covered with the third insulationfilm 13.

The main pixel electrode PA and sub-pixel electrode PB of the pixelelectrode PE, and the first main common electrodes CA1 and firstsub-common electrodes CB1 of the common electrode CE are formed on anupper surface of the same insulation film, that is, an upper surface ofthe third insulation film 13, and are mutually spaced apart. The mainpixel electrode PA is located on the inside of a position immediatelyabove each of the neighboring source line S1 and source line S2. Thefirst main common electrode CAL1 is located immediately above the sourceline S1. The first main common electrode CAR1 is located immediatelyabove the source line S2. The first sub-common electrode CBB1 is locatedimmediately above the gate line G2. The first sub-common electrode CBU1(not shown) is located immediately above the gate line G1.

A first alignment film AL1 is disposed on that surface of the arraysubstrate AR, which is opposed to the counter-substrate CT. The firstalignment film AL1 extends over substantially the entirety of the activearea ACT. The first alignment film AL1 covers the pixel electrode PE andcommon electrode CE, and is also disposed over the third insulation film13. The first alignment film AL1 is formed of a material which exhibitshorizontal alignment properties.

The counter-substrate CT is formed by using a second insulativesubstrate 20 having light transmissivity. The counter-substrate CTincludes a black matrix BM, a color filter CF, an overcoat layer OC, acommon electrode CE, and a second alignment film AL2, on the inside ofthe second insulative substrate 20, that is, on that side of the secondinsulative substrate 20, which is opposed to the array substrate AR.

The black matrix BM partitions the pixels PX. Specifically, the blackmatrix BM is disposed so as to be opposed to wiring portions, such asthe source lines S, gate lines G, storage capacitance lines C, andswitching elements. In the example illustrated, the black matrix BMincludes portions which are located above the source line S1 and sourceline S2 and extend in the second direction Y, and portions which arelocated above the gate line G2 and gate line G1 (not shown) and extendin the first direction X. The black matrix BM is disposed on an innersurface 20A of the second insulative substrate 20, which is opposed tothe array substrate AR.

The color filter CF is disposed in association with each pixel PX.Specifically, the color filter CF is disposed on an inside partitionedby the black matrix BM on the inner surface 20A of the second insulativesubstrate 20, and a part of the color filter CF extends over the blackmatrix BM. Color filters CF, which are disposed in the pixels PXneighboring in the first direction X, have mutually different colors.For example, the color filters CF are formed of resin materials whichare colored in three primary colors of red, blue and green. A red colorfilter, which is formed of a resin material that is colored in red, isdisposed in association with a red pixel. A blue color filter, which isformed of a resin material that is colored in blue, is disposed inassociation with a blue pixel. A green color filter, which is formed ofa resin material that is colored in green, is disposed in associationwith a green pixel. Boundaries between these color filters CF arelocated at positions overlapping the black matrix BM. The color filterCF includes an aperture portion AP1, as will be described later. Theaperture portion AP1 penetrates to the inner surface 20A.

The overcoat layer OC covers the color filters CF. In addition, theovercoat layer OC extends over the aperture portion AP1 and covers theinner surface 20A in the aperture portion AP1. The overcoat layer OCreduces the effect of asperities on the surface of the color filters CF.The overcoat layer OC is formed of, for example, a transparent resinmaterial.

The second main common electrodes CA2 and second sub-common electrodesCB2 of the common electrode CE are formed on that side of the overcoatlayer OC, which is opposed to the array substrate AR, and each of themis located immediately below the black matrix BM. The second main commonelectrode CAL2 is located immediately above the first main commonelectrode CAL1. The second main common electrode CAR2 is locatedimmediately above the first main common electrode CAR1. The secondsub-common electrode CBB2 is located immediately above the firstsub-common electrode CBB1. The second sub-common electrode CBU2 (notshown) is located immediately above the first sub-common electrode CBU1.

A region between the first main common electrode CAL1, second maincommon electrode CRL2 and main pixel electrode PA, and a region betweenthe first main common electrode CAR1, second main common electrode CAR2and main pixel electrode PA, correspond to transmissive regions throughwhich light can pass.

The second alignment film AL2 is disposed on that surface of thecounter-substrate CT, which is opposed to the array substrate AR, andthe second alignment film AL2 extends over substantially the entirety ofthe active area ACT. The second alignment film AL2 covers the secondmain common electrodes CA2 and second sub-common electrodes CB2 of thecommon electrode CE, and the overcoat layer OC. The second alignmentfilm AL2 is formed of a material which exhibits horizontal alignmentproperties.

The first alignment film AL1 and second alignment film AL2 are subjectedto alignment treatment (e.g. rubbing treatment or optical alignmenttreatment) for initially aligning the liquid crystal molecules of theliquid crystal layer LQ. A first alignment treatment direction PD1, inwhich the first alignment film AL1 initially aligns the liquid crystalmolecules, is parallel to a second alignment treatment direction PD2, inwhich the second alignment film AL2 initially aligns the liquid crystalmolecules. In an example shown in part (A) of FIG. 3, the firstalignment treatment direction PD1 and second alignment treatmentdirection PD2 are parallel to each other and are identical. In anexample shown in part (B) of FIG. 3, the first alignment treatmentdirection PD1 and second alignment treatment direction PD2 are parallelto each other and are opposite to each other.

The above-described array substrate AR and counter-substrate CT aredisposed such that their first alignment film AL1 and second alignmentfilm AL2 are opposed to each other. In this case, columnar spacers,which are formed of, e.g. a resin material so as to be integral to oneof the array substrate AR and counter-substrate CT, are disposed betweenthe first alignment film AL1 of the array substrate AR and the secondalignment film AL2 of the counter-substrate CT. Thereby, a predeterminedcell gap, for example, a cell gap of 2 to 7 μm, is created. The arraysubstrate AR and counter-substrate CT are attached by a sealant on theoutside of the active area ACT in the state in which the predeterminedcell gap is created therebetween.

The liquid crystal layer LQ is held in the cell gap which is createdbetween the array substrate AR and the counter-substrate CT, and isdisposed between the first alignment film AL1 and second alignment filmAL2. The liquid crystal layer LQ includes liquid crystal molecules LM.The liquid crystal layer LQ is composed of a liquid crystal materialhaving a positive (positive-type) dielectric constant anisotropy.

A first optical element OD1 is attached by, e.g. an adhesive, to anouter surface of the array substrate AR, that is, an outer surface 10Bof the first insulative substrate 10 which constitutes the arraysubstrate AR. The first optical element OD1 is located on that side ofthe liquid crystal display panel LPN, which is opposed to the backlight4, and controls the polarization state of incident light which entersthe liquid crystal display panel LPN from the backlight 4. The firstoptical element OD1 includes a first polarizer PL1 having a firstpolarization axis (or first absorption axis) AX1. In the meantime,another optical element, such as a retardation plate, may be disposedbetween the first polarizer PL1 and the first insulative substrate 10.

A second optical element OD2 is attached by, e.g. an adhesive, to anouter surface of the counter-substrate CT, that is, an outer surface 20Bof the second insulative substrate 20 which constitutes thecounter-substrate CT. The second optical element OD2 is located on thedisplay surface side of the liquid crystal display panel LPN, andcontrols the polarization state of emission light emerging from theliquid crystal display panel LPN. The second optical element OD2includes a second polarizer PL2 having a second polarization axis (orsecond absorption axis) AX2. In the meantime, another optical element,such as a retardation plate, may be disposed between the secondpolarizer PL2 and the second insulative substrate 20.

The first polarization axis AX1 of the first polarizer PL1 and thesecond polarization axis AX2 of the second polarizer PL2 have apositional relationship of crossed Nicols. In this case, one of thepolarizers is disposed such that the polarization axis thereof issubstantially parallel or substantially perpendicular to the directionof extension of the main pixel electrode PA or main common electrode CA.Specifically, when the direction of extension of the main pixelelectrode PA or main common electrode CA is the second direction Y, thepolarization axis of one of the polarizers is parallel to the seconddirection Y or is parallel to the first direction X. Alternatively, oneof the polarizers is disposed such that the polarization axis thereof isparallel or perpendicular to the initial alignment direction of liquidcrystal molecules, that is, the first alignment treatment direction PD1or second alignment treatment direction PD2. When the initial alignmentdirection is parallel to the second direction Y, the polarization axisof one of the polarizers is parallel to the second direction Y orparallel to the first direction X.

In an example shown in part (a) of FIG. 3, the first polarizer PL1 isdisposed such that the first polarization axis AX1 thereof isperpendicular to the initial alignment direction (second direction Y) ofliquid crystal molecules LM, and the second polarizer PL2 is disposedsuch that the second polarization axis AX2 thereof is parallel to theinitial alignment direction of liquid crystal molecules LM. In addition,in an example shown in part (b) of FIG. 3, the second polarizer PL2 isdisposed such that the second polarization axis AX2 thereof isperpendicular to the initial alignment direction (second direction Y) ofliquid crystal molecules LM, and the first polarizer PL1 is disposedsuch that the first polarization axis AX1 thereof is parallel to theinitial alignment direction of liquid crystal molecules LM.

Next, the operation of the liquid crystal display panel LPN having theabove-described structure is described with reference to FIG. 2 to FIG.5.

Specifically, in a state in which no voltage is applied to the liquidcrystal layer LQ, that is, in a state (OFF time) in which no electricfield is produced between the pixel electrode PE and common electrodeCE, the liquid crystal molecule LM of the liquid crystal layer LQ isaligned such that the major axis thereof is positioned in the firstalignment treatment direction PD1 of the first alignment film AL1 andthe second alignment treatment direction PD2 of the second alignmentfilm AL2. This OFF time corresponds to the initial alignment state, andthe alignment direction of the liquid crystal molecule LM at the OFFtime corresponds to the initial alignment direction.

Strictly speaking, the liquid crystal molecule LM is not always alignedin parallel to the X-Y plane, and, in many cases, the liquid crystalmolecule LM is pre-tilted. Thus, the initial alignment direction of theliquid crystal molecule LM corresponds to a direction in which the majoraxis of the liquid crystal molecule LM at the OFF time is orthogonallyprojected onto the X-Y plane. In the description below, for the purposeof simplicity, it is assumed that the liquid crystal molecule LM isaligned in parallel to the X-Y plane, and the liquid crystal molecule LMrotates in a plane parallel to the X-Y plane.

In this case, each of the first alignment treatment direction PD1 andthe second alignment treatment direction PD2 is substantially parallelto the second direction Y. At the OFF time, the liquid crystal moleculeLM is initially aligned such that the major axis thereof issubstantially parallel to the second direction Y, as indicated by abroken line in FIG. 3. Specifically, the initial alignment direction ofthe liquid crystal molecule LM is parallel to the second direction Y (or0° to the second direction Y).

When the first alignment treatment direction PD1 and the secondalignment treatment direction PD2 are parallel and identical to eachother, as in the example illustrated, the liquid crystal molecules LMare substantially horizontally aligned (the pre-tilt angle issubstantially zero) in the middle part of the liquid crystal layer LQ inthe cross section of the liquid crystal layer LQ, and the liquid crystalmolecules LM are aligned with such pre-tilt angles that the liquidcrystal molecules LM become symmetric in the vicinity of the firstalignment film AL1 and in the vicinity of the second alignment film AL2,with respect to the middle part as the boundary (splay alignment). Inthe state in which the liquid crystal molecules LM are splay-aligned,optical compensation can be made by the liquid crystal molecules LM inthe vicinity of the first alignment film AL1 and the liquid crystalmolecules LM in the vicinity of the second alignment film AL2, even in adirection inclined to the normal direction of the substrate. Therefore,when the first alignment treatment direction PD1 and the secondalignment treatment direction PD2 are parallel and identical to eachother, light leakage is small in the case of black display, a highcontrast ratio can be realized, and the display quality can be improved.

In the meantime, when the first alignment treatment direction PD1 andthe second alignment treatment direction PD2 are parallel and oppositeto each other, the liquid crystal molecules LM are aligned withsubstantially equal pre-tilt angles, in the cross section of the liquidcrystal layer LQ, in the vicinity of the first alignment film AL1, inthe vicinity of the second alignment film AL2, and in the middle part ofthe liquid crystal layer LQ (homogeneous alignment).

Part of light from the backlight 4 passes through the first polarizerPL1 and enters the liquid crystal display panel LPN. The polarizationstate of the light, which enters the liquid crystal display panel LPN,is linear polarization perpendicular to the first polarization axis AX1of the first polarizer PL1. The polarization state of such linearpolarization hardly varies when the light passes through the liquidcrystal display panel LPN at the OFF time. Thus, the linearly polarizedlight, which has passed through the liquid crystal display panel LPN, isabsorbed by the second polarizer PL2 that is in the positionalrelationship of crossed Nicols in relation to the first polarizer PL1(black display).

On the other hand, in a state in which a voltage is applied to theliquid crystal layer LQ, that is, in a state (ON time) in which apotential difference is produced between the pixel electrode PE andcommon electrode CE, a lateral electric field (or an oblique electricfield), which is substantially parallel to the substrates, is producedbetween the pixel electrode PE and the common electrode CE. The liquidcrystal molecules LM are affected by the electric field, and the majoraxes thereof rotate within a plane which is parallel to the X-Y plane,as indicated by solid lines in the Figure.

In the example shown in FIG. 3, the liquid crystal molecule LM in aregion surrounded by the pixel electrode PE, second main commonelectrode CAL2 and second sub-common electrode CBU2 (i.e. a firsttransmissive region T1 defined by the pixel electrode PE, gate line G1and source line S1 in FIG. 2) rotates counterclockwise relative to thesecond direction Y, and is aligned in a upper left direction in theFigure. The liquid crystal molecule LM in a region surrounded by thepixel electrode PE, second main common electrode CAR2 and secondsub-common electrode CBU2 (i.e. a second transmissive region T2 definedby the pixel electrode PE, gate line G1 and source line S2 in FIG. 2)rotates clockwise relative to the second direction Y, and is aligned inan upper right direction in the Figure. The liquid crystal molecule LMin a region surrounded by the pixel electrode PE, second main commonelectrode CAL2 and second sub-common electrode CBB2 (i.e. a thirdtransmissive region T3 defined by the pixel electrode PE, gate line G2and source line S1 in FIG. 2) rotates clockwise relative to the seconddirection Y, and is aligned in a lower left direction in the Figure. Theliquid crystal molecule LM in a region surrounded by the pixel electrodePE, second main common electrode CAR2 and second sub-common electrodeCBB2 (i.e. a fourth transmissive region T4 defined by the pixelelectrode PE, gate line G2 and source line S2 in FIG. 2) rotatescounterclockwise relative to the second direction Y, and is aligned in alower right direction in the Figure.

As has been described above, in the state in which the electric field isproduced between the pixel electrode PE and common electrode CE in eachpixel PX, the liquid crystal molecules LM are aligned in a plurality ofdirections, with boundaries at positions overlapping the pixel electrodePE, and domains are formed in the respective alignment directions.Specifically, a plurality of domains are formed in one pixel PX.

At such ON time, part of backlight, which is incident on the liquidcrystal display panel LPN from the backlight 4, passes through the firstpolarizer PL1, and enters the liquid crystal display panel LPN. Thelight entering the liquid crystal display panel LPN is linearlypolarized light which is perpendicular to the first polarization axisAX1 of the first polarizer PL1. The polarization state of such linearlypolarized light varies depending on the alignment state of the liquidcrystal molecules LM when the light passes through the liquid crystallayer LQ. For example, when linearly polarized light, which is parallelto the first direction X, has entered the liquid crystal display panelLPN, the light is affected, while passing through the liquid crystallayer LQ, by a retardation of λ/2 by the liquid crystal molecules whichare aligned in a 45°-225° azimuth direction or a 135°-315° azimuthdirection relative to the first direction X (λ is a wavelength of lightpassing through the liquid crystal layer LQ). Thereby, the polarizationstate of the light, which has passed through the liquid crystal layerLQ, becomes linear polarization parallel to the second direction Y.Thus, at the ON time, at least part of the light emerging from theliquid crystal layer LQ passes through the second polarizer PL2 (whitedisplay).

According to the structure of the present embodiment, the liquid crystalmolecules LM in one pixel are aligned, mainly in four directions. Inorder to realize such alignment, it should suffice if at least thesecond main common electrode CAL2 and second main common electrode CAR2are included as the common electrode CE, in addition to the pixelelectrode PE. Specifically, the first main common electrodes CA1 andfirst sub-common electrodes CB1, which are provided on the arraysubstrate AR, and the second sub-common electrodes CB2, which areprovided on the counter-substrate CT, are configured to shield anelectric field from other wiring lines, or to make stronger the electricfield that is necessary for alignment control of the liquid crystalmolecules LM, or to give redundancy to the common electrode CE, andthese components are not indispensable for forming the above-describedmultiple domains.

As regards the above structure, a study is now made of thetransmittances of one pixel PX at an OFF time (black display) and attimes when gray-scale display is effected.

FIG. 6 shows light transmission states at times when black display,low-gray-level display, intermediate-gray-level display andhigh-gray-level display (white display) were effected.

Long-side silhouettes along the second direction Y of the pixel shown inFIG. 6 are silhouettes of the source lines S, first main commonelectrodes CA1 and second main common electrodes CA2, or silhouettes ofthe black matrix BM. Short-side silhouettes along the first direction Xof the pixel are silhouettes of the gate lines G, first sub-commonelectrodes CB1 and second sub-common electrodes CB2, or silhouettes ofthe black matrix BM. Cross-shaped silhouette intersecting at the centerof the pixel are silhouettes of the pixel electrode PE and storagecapacitance line C.

At the time of black display, light hardly passes through the entiretyof one pixel, and the transmittance becomes substantially zero. At thetime of high-gray-level display, light passes through four regions inone pixel, i.e. first to fourth transmissive regions, and thetransmittance becomes maximum.

At the time of low-gray-level display and intermediate-gray-leveldisplay, like the high-gray-level display, light passes through thefirst to fourth transmissive regions, but dark areas occur at thecentral part and corner parts of the pixel. In particular, such darkareas become broader at the time of low-gray-level display. Such darkareas occur because an electric field enough to rotate liquid crystalmolecules LM is not applied to the liquid crystal layer LQ and theliquid crystal molecules LM maintain the initial alignment state.

Referring to FIG. 2, the dark areas at the central part of the pixel areformed over the pixel electrode, over the storage capacitance line, overthe area where the pixel electrode is opposed to the storage capacitanceline, as well as over those parts of the first to fourth transmissiveregions, which include cross points between the main pixel electrode PAand sub-pixel electrode PB. In addition, dark areas are formed at cornerparts near intersections between the gate lines and source lines. Eachdark area has a polygonal shape or an oval shape (including an ellipticshape). For example, dark areas spreading to the first to fourthtransmissive regions from the cross points between the main pixelelectrode PA and sub-pixel electrode PB and from the corner parts aresubstantially triangular.

FIG. 7 is a plan view which schematically illustrates the shape of thecolor filter in the embodiment. In FIG. 7, the pixel electrode PE, gateline G1, gate line G2, source line S1, source line S2 and storagecapacitance line C1 are indicated by broken lines. The positions wherethe gate line G1 and gate line G2, as well as the source line S1 andsource line S2, are formed substantially agree with the position wherethe black matrix is formed.

In the example illustrated, a green pixel PXG, a red pixel PXR and ablue pixel PXB are successively arranged in the first direction X. Agreen color filter CFG is disposed in the green pixel PXG, a red colorfilter CFR is disposed in the red pixel PXR, and a blue color filter CFBis disposed in the blue pixel PXB. In the description below, the redcolor filter CFR of the red pixel PXR is described. Since the greencolor filter CFG of green pixel PXG and the blue color filter CFB ofblue pixel PXB have the same structure as the red color filter CFR, adescription thereof is omitted.

Attention is now paid to the first transmissive region T1 which isinside the gate line G1, storage capacitance line C1, source line S1 andpixel electrode PE. In the first transmissive region T1, the red colorfilter CFR extends from an intersection part CR1 between the source lineS1 and storage capacitance line C1 in a direction which is differentfrom the first direction X and second direction Y, i.e. in a directionin a range θa which is greater than 0° and is less than 90°, relative tothe first direction X. Specifically, in the case where the firsttransmissive region T1 is substantially rectangular, the red colorfilter CFR extends along a diagonal line connecting the intersectionpart CR1 and a position where the pixel electrode PE and gate line G1are close to each other.

In other words, in the first transmissive region T1, the red colorfilter CFR includes an aperture portion AP1 which faces a positionopposed to a cross point CP1 between the main pixel electrode PA andsub-pixel electrode PB. Specifically, an edge of the aperture portionAP1 surrounds the position opposed to the cross point CP1. The apertureportion AP1 is formed so as to be opposed to the dark area spreadingfrom the cross point CP1 to the first transmissive region T1, and isopposed to, for example, a triangular area having the cross point CP1 asan apex. In addition, the red color filter CFR includes an apertureportion AP21 which faces a position opposed to a corner part CN1 whichis located at a cross part CR41 between the gate line G1 and source lineS1. Specifically, an edge of the aperture portion AP21 surrounds theposition opposed to the corner part CN1. The opening portion AP21 isformed so as to be opposed to the dark area spreading from the cornerpart CN1 to the first transmissive region T1, and is opposed to, forexample, a triangular area having the corner part CN1 as an apex. In thesubstantially rectangular first transmissive region T1, the cross pointCP1 is located at an opposite angle to the corner part CN1, and theaperture portion AP21 is located at an opposite angle to the apertureportion AP1.

The same applies to the second transmissive region T2 of the red pixelPXR, and the red color filter CFR extends from an intersection part CR2between the source line S2 and storage capacitance line C1 in adirection in a range θb which is greater than 90° and is less than 180°,relative to the first direction X. In the fourth transmissive region T4of the red pixel PXR, the red color filter CFR extends from theintersection part CR2 in a direction in a range θc which is greater than180° and is less than 270°, relative to the first direction X. In thethird transmissive region T3 of the red pixel PXR, the red color filterCFR extends from the intersection part CR1 in a direction in a range θdwhich is greater than 270° and is less than 360°, relative to the firstdirection X.

The aperture portion AP1 of the red color filter CFR faces the positionopposed to the cross points CP2 to CP4. In other words, the edge of theaperture portion AP1 surrounds the position opposed to the cross pointsCP2 to CP4. Specifically, the aperture portion AP1 is formed so as to beopposed to the dark area spreading from the cross point CP2 to thesecond transmissive region T2, the dark area spreading from the crosspoint CP3 to the third transmissive region T3, and the dark areaspreading from the cross point CP4 to the fourth transmissive region T4.

Further, the red color filter CFR includes aperture portions AP22 toAP24. The aperture portion AP22 is formed so as to face a positionopposed to a corner part CN2 near a cross part CR42 between the gateline G1 and source line S2, and to be opposed to the dark area spreadingfrom the corner part CN2 to the second transmissive region T2.Specifically, an edge of the aperture portion AP22 surrounds theposition opposed to the corner part CN2. The aperture portion AP23 isformed so as to face a position opposed to a corner part CN3 near across part CR43 between the gate line G2 and source line S1, and to beopposed to the dark area spreading from the corner part CN3 to the thirdtransmissive region T3. Specifically, an edge of the aperture portionAP23 surrounds the position opposed to the corner part CN3. The apertureportion AP24 is formed so as to face a position opposed to a corner partCN4 near a cross part CR44 between the gate line G2 and source line S2,and to be opposed to the dark area spreading from the corner part CN4 tothe fourth transmissive region T4. Specifically, an edge of the apertureportion AP24 surrounds the position opposed to the corner part CN4. Theaperture portions AP21 to AP24 have substantially the same shape.

Paying attention to one pixel defined by the gate line G1, gate line G2,source line S1 and source line S2, the red color filter CFR includes theaperture portion AP1 formed at the central part of the red pixel PXR andthe aperture portions AP21 to AP24 formed at the four corner parts, andthe red color filter CFR is formed in a doughnut shape. Like theaperture portion AP1 shown in FIG. 5, the locations where the apertureportions AP21 to AP24 are formed are covered with the overcoat layer OC.

In the example illustrated, the aperture portion AP1 and apertureportions AP21 to AP24 have a polygonal shape (e.g. octagon) elongated inthe second direction Y, but the aperture portion AP1 and apertureportions AP21 to AP24 may have an oval shape (or elliptic shape)elongated in the second direction Y. The edges, which define theaperture portion AP1 and aperture portions AP21 to AP24, do not need tobe straight, but may be partly curved. Although the aperture portion AP1is commonly formed at positions opposed to the cross points CP1 to CP4centering at the sub-pixel electrode PB, the aperture portion AP1 may beformed so as to be separately opposed to the four cross points CP1 toCP4. In this case, the aperture portion AP1 is separated into fouraperture portions at the central part of the pixel. However, it isdesirable to form, if possible, the common aperture portion, since astepped portion tends to easy form between the part where the colorfilter is formed and the part where aperture portion is formed.

The aperture portion AP1 and aperture portions AP21 to AP24 are opposedto the dark areas which occur when low-gray-level display is effected asshown in FIG. 6. Thus, when low-gray-level display is effected, lightleakage hardly occurs from the aperture portion AP1 and apertureportions AP21 to AP24, and backlight mainly passes through the colorfilter. Accordingly, even in the case where the color filter of thepresent embodiment is applied, when the low-gray-level display iseffected, most of backlight in the red pixel PXR passes through the redcolor filter CFR, most of backlight in the green pixel PXG passesthrough the green color filter CFG, and most of backlight in the bluepixel PXB passes through the blue color filter CFB. Therefore,degradation in color purity at a time of low-gray-level display can besuppressed. Specifically, when the low-gray-level display is effected,compared to the case where the color filter having no aperture portionis applied, substantially the same range of color reproduction can bemaintained.

On the other hand, when high-gray-level display is effected, backlightpasses through the color filter and also passes through the apertureportion AP1 and aperture portion AP21 to AP24. The light, which haspassed through the aperture portion AP1 and aperture portion AP21 toAP24, is substantially white light. At the time of high-gray-leveldisplay, in the red pixel PXR, most of backlight passes through the redcolor filter CFR, and part of the backlight passes through the apertureportion AP1 and aperture portions AP21 to AP24. Thus, although the colorpurity of red lowers, the luminance in the red pixel PXR can beimproved. Similarly, in the green pixel PXG, most of backlight passesthrough the green color filter CFG and part of the backlight passesthrough the aperture portions. Thus, although the color purity of greenlowers, the luminance in the green pixel PXG can be improved. Similarly,in the blue pixel PXB, most of backlight passes through the blue colorfilter CFB and part of the backlight passes through the apertureportions. Thus, although the color purity of blue lowers, the luminancein the blue pixel PXB can be improved.

FIG. 8 is a graph showing an example of spectral transmittances of therespective color filters and a spectral transmittance at the apertureportion.

The spectral transmittance, which is obtained by the red color filterCFR, is highest in the neighborhood of a red wavelength λr (e.g. 650nm). The spectral transmittance, which is obtained by the green colorfilter CFG, is highest in the neighborhood of a green wavelength λg(e.g. 550 nm). The spectral transmittance, which is obtained by the bluecolor filter CFB, is highest in the neighborhood of a blue wavelength λb(e.g. 450 nm). The spectral transmittance, which is obtained at theaperture portion AP1 and aperture portions AP21 to AP24, corresponds tothe spectral transmittance of white light.

In the red pixel PXR, when low-gray-level display is effected, a colorcorresponding to the spectral transmittance obtained by the red colorfilter CFR is displayed, and when high-gray-level display is effected, acolor in which the spectral transmittance of white light is added to thespectral transmittance obtained by the red color filter CFR isdisplayed. Similarly, in the green pixel PXG, when low-gray-leveldisplay is effected, a color corresponding to the spectral transmittanceobtained by the green color filter CFG is displayed, and whenhigh-gray-level display is effected, a color in which the spectraltransmittance of white light is added to the spectral transmittanceobtained by the green color filter CFG is displayed. Similarly, in theblue pixel PXB, when low-gray-level display is effected, a colorcorresponding to the spectral transmittance obtained by the blue colorfilter CFB is displayed, and when high-gray-level display is effected, acolor in which the spectral transmittance of white light is added to thespectral transmittance obtained by the blue color filter CFB isdisplayed.

FIG. 9 is a chromaticity diagram showing an example of a colorreproduction range at a time of low-gray-level display and a colorreproduction range at a time of high-gray-level display in a case wherethe color filters of the embodiment are applied. FIG. 9 shows colorreproduction ranges by a CIExy chromaticity diagram.

At a time of low-gray-level display, since the color corresponding tothe spectral transmittance of the red color filter CFR is displayed inthe red pixel PXR, a red color with high color purity is displayed.Similarly, a green color with high color purity is displayed in thegreen pixel PXG, and a blue color with high color purity is displayed inthe blue pixel PXB. Thus, when low-gray-level display is effected, arelatively wide color reproduction range can be obtained.

When high-gray-level display is effected, the color in which thespectral transmittance of white light is added to the spectraltransmittance obtained by the red color filter CFR is displayed in thered pixel PXR. Specifically, when high-gray-level display is effected,the chromaticity coordinates shift to the white side, compared to thecolor corresponding to the spectral transmittance of the red colorfilter CFR as in the case of the low-gray-level display. Accordingly, atthe time of high-gray-level display, the color purity of red becomeslower than in the case of the low-gray-level display. Similarly, thechromaticity coordinates of green at the time of high-gray-level displayin the green pixel PXG shift to the white side, compared to the case oflow-gray-level display, and the chromaticity coordinates of blue at thetime of high-gray-level display in the blue pixel PXB shift to the whiteside, compared to the case of low-gray-level display. Accordingly, atthe time of high-gray-level display, compared to low-gray-level display,the color reproduction range becomes narrower. Meanwhile, at the time ofhigh-gray-level display, white light, which passes through the apertureportions of the color filter in each pixel, contributes to display.Therefore, in each of the red pixel PXR, green pixel PXG and blue pixelPXB, a high brightness can be obtained at the time of high-gray-leveldisplay, compared to the case where the color filter having no apertureportion is applied.

According to the present embodiment, when low-gray-level display iseffected, no light leakage occurs and a wide color reproduction rangecan be obtained. When high-gray-level display is effected, a highbrightness can be obtained. Therefore, the display quality can beimproved.

According to the present embodiment, a high transmittance can beobtained in the inter-electrode gap between the pixel electrode PE andthe common electrode CE. Thus, a transmittance per pixel cansufficiently be increased by increasing the inter-electrode distancebetween the pixel electrode PE and the main common electrode CA. Asregards product specifications in which the pixel pitch is different,the peak condition of the transmittance distribution can be used byvarying the inter-electrode distance (e.g. by varying the position ofdisposition of the main common electrode CA in relation to the mainpixel electrode PA). Specifically, in the display mode of the presentembodiment, products with various pixel pitches can be provided bysetting the inter-electrode distance, without necessarily requiring fineelectrode processing, as regards the product specifications fromlow-resolution product specifications with a relatively large pixelpitch to high-resolution product specifications with a relatively smallpixel pitch. Therefore, requirements for high transmittance and highresolution can easily be realized.

According to the present embodiment, the transmittance is sufficientlylowered in the region overlapping the black matrix BM. The reason forthis is that the electric field does not leak to the outside of thepixel from the position of the common electrode CE, and an undesiredlateral electric field does not occur between pixels which neighbor eachother with the black matrix BM interposed, and therefore the liquidcrystal molecules LM in the region overlapping the black matrix BM keepthe initial alignment state, like the case of the OFF time (or blackdisplay time). Accordingly, even when the colors of the color filters CFare different between neighboring pixels, the occurrence of colormixture can be suppressed, and the decrease in color reproducibility orthe decrease in contrast ratio can be suppressed.

When misalignment occurs between the array substrate AR and thecounter-substrate CT, there are cases in which a difference occurs inthe inter-electrode distance between the pixel electrode PE and thecommon electrodes CE on both sides of the pixel electrode PE. However,since such misalignment commonly occurs in all pixels PX, the electricfield distribution does not differ between the pixels PX, and theinfluence on the display of images is very small. In addition, even whenmisalignment occurs between the array substrate AR and thecounter-substrate CT, leakage of an undesired electric field to theneighboring pixel can be suppressed. Thus, even when the colors of thecolor filters CF differ between neighboring pixels, the occurrence ofcolor mixture can be suppressed, and the decrease in colorreproducibility or the decrease in contrast ratio can be suppressed.

According to the present embodiment, the main common electrodes CA areopposed to the source lines S. In particular, in the case where the maincommon electrode CAL and main common electrode CAR are disposed abovethe source line S1 and source line S2, compared to the case where themain common electrode CAL and main common electrode CAR are disposed onthe pixel electrode PE side of the source line S1 and source line S2,the transmissive region can be enlarged and the transmittance of thepixel PX can be enhanced. In addition, by disposing the main commonelectrode CAL and main common electrode CAR above the source line S1 andsource line S2, the inter-electrode distance between the pixel electrodePE, on the one hand, and the main common electrode CAL and main commonelectrode CAR, on the other hand, can be increased, and a lateralelectric field, which is closer to a horizontal lateral electric field,can be produced. Therefore, a wide viewing angle, which is the advantageof an IPS mode, etc. in the conventional structure, can be maintained.

According to the present embodiment, a plurality of domains can beformed in one pixel. Thus, the viewing angle can optically becompensated in plural directions, and a wide viewing angle can berealized.

According to the present embodiment, the array substrate AR includes thefirst main common electrodes CA1 which are located on both sides of thepixel electrode PE. Since the first main common electrodes CA1 arebroken at positions neighboring the sub-pixel electrode PB, even if thewidth in the first direction X of the sub-pixel electrode PB increasesor the width in the first direction X of the pixel PX decreases, it ispossible to sufficiently secure a horizontal inter-electrode distancebetween the sub-pixel electrode PB having a pixel potential and thefirst main common electrode CA1 having a common potential. Therefore, itis possible to suppress the occurrence of a display defect due toshort-circuit between the pixel electrode PE and the common electrodeCE. In addition, it is possible to adapt to a narrow pixel pitch in acase where the pixel pitch in the first direction X is decreased, andmicrofabrication with higher fineness can be achieved.

Furthermore, since the first main common electrode CA1 is opposed to thesource line S, an undesired electric field from the source line S can beshielded. It is thus possible to suppress application of an undesiredbias from the source line S to the liquid crystal layer LQ, and tosuppress the occurrence of a display defect such as crosstalk (e.g. aphenomenon that when a pixel potential for displaying white is suppliedto the source line that is connected to the pixel PX in the state inwhich the pixel PX is set at a pixel potential for displaying black,light leaks from a part of the pixel PX and the brightness increases).

Since the first sub-common electrode CB1 is opposed to the gate line G,an undesired electric field from the gate line G can be shielded. It isthus possible to suppress application of an undesired bias from the gateline G to the liquid crystal layer LQ, and to suppress the occurrence ofa display defect such as burn-in, and the occurrence of light leakagedue to an alignment defect of liquid crystal molecules.

Since the first main common electrodes CA1 and first sub-commonelectrodes CB1 are electrically connected and formed in a substantiallygrid-like shape, redundancy can be improved. In addition, since thesecond main common electrodes CA2 and second sub-common electrodes CB2are electrically connected and formed in a substantially grid-likeshape, redundancy can be improved. Accordingly, even if breakage occursin a part of the common electrode CE that is provided on the arraysubstrate AR or breakage occurs in a part of the common electrode CEthat is provided on the counter-substrate CT, the common potential canstably be supplied to each pixel PX, and the occurrence of a displaydefect can be suppressed.

The above-described example is directed to the case where the initialalignment direction of liquid crystal molecules LM is parallel to thesecond direction Y. However, the initial alignment direction of liquidcrystal molecules LM may be an oblique direction D which obliquelycrosses the second direction Y, as shown in FIG. 3. An angle θ1 formedbetween the second direction Y and the initial alignment direction D is0° or more and 45° or less. From the standpoint of alignment control ofliquid crystal molecules LM, it is very effective that the angle θ1 isabout 5° to 30°, more preferably 20° or less. Specifically, it isdesirable that the initial alignment direction of liquid crystalmolecules LM be substantially parallel to a direction in a range of 0°or more and 20° or less, relative to the second direction Y.

The above-described example relates to the case in which the liquidcrystal layer LQ is composed of a liquid crystal material having apositive (positive-type) dielectric constant anisotropy. Alternatively,the liquid crystal layer LQ may be composed of a liquid crystal materialhaving a negative (negative-type) dielectric constant anisotropy.Although a detailed description is omitted, in the case of thenegative-type liquid crystal material, since the positive/negative stateof dielectric constant anisotropy is reversed, it is desirable that theabove-described formed angle θ1 be within the range of 45° to 90°,preferably the range of 70° or more and 90° or less.

Since a lateral electric field is hardly produced over the pixelelectrode PE or common electrode CE even at the ON time (or an electricfield enough to drive liquid crystal molecules LM is not produced), theliquid crystal molecules LM scarcely move from the initial alignmentdirection, like the case of the OFF time. Thus, even if the pixelelectrode PE and common electrode CE are formed of a light-transmissive,electrically conductive material such as ITO, little backlight passesthrough these regions, and these regions hardly contribute to display atthe ON time. Thus, the pixel electrode PE and common electrode CE do notnecessarily need to be formed of a transparent, electrically conductivematerial, and may be formed of an opaque wiring material such asaluminum (Al), titanium (Ti), silver (Ag), molybdenum (Mo), or tungsten(W).

Next, other structures of the embodiment are described.

FIG. 10 is a plan view which schematically illustrates another shape ofthe color filter in the embodiment. In the illustrated structureexample, the storage capacitance line C1 is located with such a bias asto be closer to the gate line G2 than to the gate line G1. Specifically,the distance in the second direction Y between the storage capacitanceline C1 and the gate line G2 is less than the distance in the seconddirection Y between the storage capacitance line C1 and the gate lineG1. In this structure example, compared to the structure example shownin FIG. 7, the positions of aperture portions, which are formed in thecolor filter, are different. In the other respects, this structureexample is the same as the structure example shown in FIG. 7, and thesame parts are denoted by like reference numerals and a detaileddescription thereof is omitted.

In the description below, the structure of the red pixel PXR, in whichthe red color filter CFR is disposed, is described. Since the greenpixel PXG and blue pixel PXB have the same structure, a descriptionthereof is omitted.

In the red pixel PXR which is defined by the gate line G1, gate line G2,source line S1 and source line S2, the pixel electrode PE includes asub-pixel electrode PB, which is opposed to the storage capacitance lineC1, and a strip-shaped main pixel electrode PA, which linearly extendsfrom the sub-pixel electrode PB toward the gate line G1, and the pixelelectrode PE is formed in a T shape.

Attention is now paid to the first transmissive region (the left-sideregion of the red pixel PXR) T1 which is inside the gate line G1,storage capacitance line C1, source line S1 and pixel electrode PE. Inthe first transmissive region T1, the red color filter CFR extends fromthe intersection part CR1 in a direction in a range θa which is greaterthan 0° and is less than 90°, relative to the first direction X.Specifically, in the first transmissive region T1 that is substantiallyrectangular, the red color filter CFR extends along a diagonal lineconnecting the intersection part CR1 and a position where the main pixelelectrode PA and gate line G1 are close to each other.

In other words, in the first transmissive region T1, the red colorfilter CFR includes an aperture portion AP1 which faces a positionopposed to a cross point CP1 between the main pixel electrode PA andsub-pixel electrode PB. Specifically, an edge of the aperture portionAP1 surrounds the position opposed to the cross point CP1. The apertureportion AP1 is formed so as to be opposed to the dark area spreadingfrom the cross point CP1 to the first transmissive region T1. Forexample, the aperture portion AP1 is opposed to a triangular area havingthe cross point CP1 as an apex. In addition, the red color filter CFRincludes an aperture portion AP21 which faces a position opposed to acorner part CN1 which is located at a cross part CR41 between the gateline G1 and source line S1. Specifically, an edge of the apertureportion AP21 surrounds the position opposed to the corner part CN1. Theopening portion AP21 is formed so as to be opposed to the dark areaspreading from the corner part CN1 to the first transmissive region T1,and is opposed to, for example, a triangular area having the corner partCN1 as an apex. In the substantially rectangular first transmissiveregion T1, the cross point CP1 is located at an opposite angle to thecorner part CN1, and the aperture portion AP21 is located at an oppositeangle to the aperture portion AP1.

In the second transmissive region (the right-side region of the redpixel PXR) T2 which is inside the gate line G1, storage capacitance lineC1, source line S2 and pixel electrode PE, the red color filter CFRextends from the intersection part CR2 in a direction in a range θbwhich is greater than 90° and is less than 180°, relative to the firstdirection X. The aperture portion AP1 is formed so as to be opposed tothe dark area spreading from the cross point CP2 to the secondtransmissive region T2. Further, the red color filter CFR includes anaperture portion AP22 which faces a position opposed to a corner partCN2 located at a cross part CR42 between the gate line G1 and sourceline S2. Specifically, an edge of the aperture portion AP22 surroundsthe position opposed to the corner part CN2. The aperture portion AP22is formed so as to be opposed to the dark area spreading from the cornerpart CN2 to the second transmissive region T2. In the substantiallyrectangular second transmissive region T2, the cross point CP2 islocated at an opposite angle to the corner part CN2, and the apertureportion AP22 is located at an opposite angle to the aperture portionAP1. The aperture portion AP21 and aperture portion AP22 havesubstantially the same shape. Although the shapes of the apertureportion AP1 and aperture portions AP21 and AP22 are polygonal in theillustrated example, the shapes are not limited to this example.

Paying attention to one pixel defined by the gate line G1, gate line G2,source line S1 and source line S2, the red color filter CFR includes theaperture portion AP1 formed on the gate line G2 side of the central partof the red pixel PXR, and the aperture portion AP21 and aperture portionAP22 formed at the two corner parts, and the red color filter CFR isformed in a U shape.

Like the structure example illustrated in FIG. 7, the aperture portionAP1 and the aperture portions AP21 and AP22 are formed at positionscorresponding to dark areas which occur when low-gray-level display iseffected. Therefore, in this structure example, too, when low-gray-leveldisplay is effected, light leakage hardly occurs from the apertureportion AP1 and aperture portions AP21 and AP22, and a wide colorreproduction range can be obtained. In addition, when high-gray-leveldisplay is effected, a high brightness can be obtained.

FIG. 11 is a plan view which schematically illustrates another shape ofthe color filter in the embodiment. In the illustrated structureexample, like the structure example shown in FIG. 10, the storagecapacitance line C1 is located with such a bias as to be closer to thegate line G2 than to the gate line G1. In this structure example,compared to the structure example shown in FIG. 7, the shape of thepixel electrode and the positions of aperture portions, which are formedin the color filter, are different.

In the red pixel PXR which is defined by the gate line G1, gate line G2,source line S1 and source line S2, the pixel electrode PE includes amain pixel electrode PA, a sub-pixel electrode PB1, which is continuouswith one end side of the main pixel electrode PA and is opposed to thestorage capacitance line C1, and a sub-pixel electrode PB2 which iscontinuous with the other end side of the main pixel electrode PA, andthe pixel electrode PE is formed in an I shape.

In the first transmissive region T1 which is inside the gate line G1,storage capacitance line C1, source line S1 and pixel electrode PE, thered color filter CFR includes an aperture portion AP1 which faces aposition opposed to a cross point CP1 between the main pixel electrodePA and sub-pixel electrode PB1, and an aperture portion AP2 which facesa position opposed to a cross point CP2 between the main pixel electrodePA and sub-pixel electrode PB2. The aperture portion AP1 is formed so asto be opposed to the dark area spreading from the cross point CP1 to thefirst transmissive region T1. The aperture portion AP2 is formed so asto be opposed to the dark area spreading from the cross point CP2 to thefirst transmissive region T1.

In the second transmissive region T2 which is inside the gate line G1,storage capacitance line C1, source line S2 and pixel electrode PE, theaperture portion AP1 of the red color filter CFR faces a positionopposed to a cross point CP3 between the main pixel electrode PA and thesub-pixel electrode PB1, and the aperture portion AP2 faces a positionopposed to a cross point CP4 between the main pixel electrode PA and thesub-pixel electrode PB2.

Like the structure example illustrated in FIG. 7, the aperture portionAP1 and the aperture portion AP2 are formed at positions correspondingto dark areas which occur when low-gray-level display is effected.Therefore, in this structure example, too, when low-gray-level displayis effected, light leakage hardly occurs from the aperture portion AP1and aperture portion AP2, and a wide color reproduction range can beobtained. In addition, when high-gray-level display is effected, a highbrightness can be obtained.

In the above-described three structure examples, for example, the part,at which the main pixel electrode PA and sub-pixel electrode PBintersect, is a part where liquid crystal molecules less easily respondto an electric field than in other parts in one pixel. Thus, the part,at which the main pixel electrode PA and sub-pixel electrode PBintersect, is a part where the brightness is lower than in the otherparts. However, the brightness in a gray scale from a low gray level toa high gray level can be improved by disposing a transparent orcolorless material, in place of the color filter, in that part whereliquid crystal molecules less easily respond to an electric field, as ineach of the above-described structure examples.

In the present embodiment, the structure of the pixel PX is not limitedto the above-described example.

In the above-described example, the structure, in which the storagecapacitance line is disposed immediately below the sub-pixel electrodePB, has been described. However, the gate line may be disposedimmediately below the sub-pixel electrode PB. In addition, in theabove-described example, the case has been described that the directionof extension of the main pixel electrode PA is the second direction Y.However, the main pixel electrode PA may extend in the first directionX. In this case, the direction of extension of the main common electrodeCA is the first direction X. Besides, in the above-described example,the case has been described that the common electrode CE including themain common electrodes CA, which are located on both sides of the mainpixel electrode, are provided in association with the pixel electrode PEincluding the main pixel electrode PA. However, the pixel electrode PEincluding main pixel electrodes PA, which are located on both sides ofthe main common electrode, may be provided in association with thecommon electrode CE including the main common electrode CA.

As has been described above, according to the present embodiments, aliquid crystal display device which can suppress degradation in displayquality can be provided.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A liquid crystal display device comprising: afirst substrate including a first gate line and a second gate line whichextend in a first direction, a storage capacitance line which extends inthe first direction between the first gate line and the second gateline, a first source line and a second source line which extend in asecond direction crossing the first direction, a switching element whichis electrically connected to the first gate line and the first sourceline, a main pixel electrode which extends in the second directionbetween the first source line and the second source line, a sub-pixelelectrode which extends in the first direction, is electricallyconnected to the switching element, crosses the main pixel electrode andis continuous with the main pixel electrode, and a first alignment filmwhich covers the main pixel electrode and the sub-pixel electrode; asecond substrate including a color filter which includes a firstaperture portion defined by a first edge surrounding a position opposedto cross points between the main pixel electrode and the sub-pixelelectrode, an overcoat layer which covers the color filter and extendsover the first aperture portion, main common electrodes which extend inthe second direction on both sides of the main pixel electrode on thatside of the overcoat layer, which is opposed to the first substrate, anda second alignment film which covers the main common electrodes; and aliquid crystal layer including liquid crystal molecules held between thefirst substrate and the second substrate.
 2. The liquid crystal displaydevice of claim 1, wherein the color filter extends in a direction,which is different from the first direction and the second direction,from a first intersection part between the first source line and thestorage capacitance line and from a second intersection part between thesecond source line and the storage capacitance line.
 3. The liquidcrystal display device of claim 2, wherein the color filter extendsalong a diagonal line from the first intersection part in a firsttransmissive region having a substantially rectangular shape defined bythe main pixel electrode, the sub-pixel electrode, the first gate lineand the first source line, and extends along a diagonal line from thesecond intersection part in a second transmissive region having asubstantially rectangular shape defined by the main pixel electrode, thesub-pixel electrode, the first gate line and the second source line. 4.The liquid crystal display device of claim 3, wherein the cross pointsopposed to the first aperture portion include a first cross pointlocated at an opposite angle to a first corner part which is located ata position where the first gate line and the first source line intersectin the first transmissive region, and a second cross point located at anopposite angle to a second corner part which is located at a positionwhere the first gate line and the second source line intersect in thesecond transmissive region.
 5. The liquid crystal display device ofclaim 4, wherein the first aperture portion is opposed to a first areaspreading from the first cross point to the first transmissive region,and a second area spreading from the second cross point to the secondtransmissive region.
 6. The liquid crystal display device of claim 5,wherein the first area has a triangular shape having the first crosspoint as an apex, and the second area has a triangular shape having thesecond cross point as an apex.
 7. The liquid crystal display device ofclaim 6, wherein the color filter further includes a second apertureportion defined by a second edge surrounds a position opposed to thefirst corner part, and a third aperture portion defined by a third edgesurrounds a position opposed to the second corner part.
 8. The liquidcrystal display device of claim 7, wherein the second aperture portionis opposed to a third area spreading from the first corner part to thefirst transmissive region, and the third aperture portion is opposed toa fourth area spreading from the second corner part to the secondtransmissive region.
 9. The liquid crystal display device of claim 8,wherein the third area has a triangular shape having the first cornerpart as an apex, and the fourth area has a triangular shape having thesecond corner part as an apex.
 10. The liquid crystal display device ofclaim 1, wherein the storage capacitance line is located at asubstantially middle point between the first gate line and the secondgate line, and the sub-pixel electrode is formed at a position opposedto the storage capacitance line.
 11. The liquid crystal display deviceof claim 10, wherein the first aperture portion is formed at a centralpart of a pixel which is defined by the first gate line, the second gateline, the first source line and the second source line.
 12. The liquidcrystal display device of claim 11, wherein the color filter is formedin a doughnut shape in the pixel.
 13. The liquid crystal display deviceof claim 1, wherein the storage capacitance line is located with such abias as to be closer to the second gate line than to the first gateline, and the sub-pixel electrode is formed at a position opposed to thestorage capacitance line.
 14. The liquid crystal display device of claim13, wherein the first aperture portion is formed on the second gate lineside of a central part of a pixel which is defined by the first gateline, the second gate line, the first source line and the second sourceline.
 15. The liquid crystal display device of claim 14, wherein thecolor filter is formed in a U shape in the pixel.
 16. The liquid crystaldisplay device of claim 1, wherein in a state in which an electric fieldis not produced between the main pixel electrode and the main commonelectrode, an initial alignment direction of the liquid crystalmolecules is substantially parallel to the second direction, and theliquid crystal molecules are splay-aligned or homogeneously alignedbetween the first substrate and the second substrate.
 17. The liquidcrystal display device of claim 16, further comprising a first polarizerwhich is disposed on an outer surface of the first substrate andincludes a first polarization axis, and a second polarizer which isdisposed on an outer surface of the second substrate and includes asecond polarization axis having a positional relationship of crossedNicols with the first polarization axis, the first polarization axisbeing perpendicular or parallel to the initial alignment direction. 18.A liquid crystal display device comprising: a first substrate includinga first gate line and a second gate line which extend in a firstdirection, a storage capacitance line which extends in the firstdirection at a substantially middle point between the first gate lineand the second gate line, a first source line and a second source linewhich extend in a second direction crossing the first direction, aswitching element which is electrically connected to the first gate lineand the first source line, a cross-shaped pixel electrode including amain pixel electrode, which extends in the second direction between thefirst source line and the second source line, and a sub-pixel electrode,which is located above the storage capacitance line, is electricallyconnected to the switching element, crosses the main pixel electrode andextends in the first direction, and a first alignment film which coversthe pixel electrode; a second substrate including a color filter whichincludes a first aperture portion defined by a first edge surrounding aposition opposed to first to fourth cross points between the main pixelelectrode and the sub-pixel electrode at a central part of the pixel, anovercoat layer which covers the color filter and extends over the firstaperture portion, main common electrodes which extend in the seconddirection on both sides of the main pixel electrode on that side of theovercoat layer, which is opposed to the first substrate, and a secondalignment film which covers the main common electrodes; and a liquidcrystal layer including liquid crystal molecules held between the firstsubstrate and the second substrate.
 19. The liquid crystal displaydevice of claim 18, wherein the color filter further includes a secondaperture portion defined by a second edge surrounding a position opposedto a first corner part which is located at a position where the firstgate line and the first source line intersect, a third aperture portiondefined by a third edge surrounding a position opposed to a secondcorner part which is located at a position where the first gate line andthe second source line intersect, a fourth aperture portion defined by afourth edge surrounding a position opposed to a third corner part whichis located at a position where the second gate line and the first sourceline intersect, and a fifth aperture portion defined by a fifth edgesurrounding a position opposed to a fourth corner part which is locatedat a position where the second gate line and the second source lineintersect.
 20. The liquid crystal display device of claim 19, whereinthe second to fifth aperture portions have the same shape.